Struts 2 Architecture

✔ STRUTS 2 CHAPTERS:-

1. Struts2 Overview
2. Struts2 Architecture
3. Struts2 Configuration Files
4. Action in Struts2
5. Action in Struts2 by using Pojo Class
6. Action in struts2 by Implementing Action Interface
7. Action in Struts2 by Extending Action Support Class
8. Struts2 Hello World Example
9. Multiple Configuration File in Struts2
10. OGNL in Struts2
11. Value Stack in Struts2
12. Interceptors in Struts2
13. Struts2 Execandwait Interceptor
14. Struts2 Custom Interceptor
15. Struts2 Result type
16. Struts2 Redirect result type
17. Struts2 Validation Framework
18. Struts2 Validation by Built in validators
19. Struts2 i18n
20. Struts2 Zero Configuration by convention approach
21. Struts2 Zero Configuration by annotation Approach
22. Dispatch Action Functionality in Struts2
23. Dynamic method invocation in Struts2
24. Struts2 UI Tags
25. Struts2 Control Tags
26. Struts2 Data Tags
27. Struts2 and tiles integration
28. Struts2 and Quartz2 Schedular
29. Struts2 Interview Questions and Answers

Struts 2 MVC framework contains the following core components:

1. 1. Actions.
2. 2. Interceptors.
3. 3. Value Stack / OGNL
4. 4. Result types

Diagram:

Struts 2 request life cycle:

1. 1. When a request comes web container maps the request in the web.xml and calls the controller (FilterDispatcher).
2. 2. FilterDispatcher calls the ActionMapper to find an Action to be invoked.
3. 3. FilterDispatcher calls the ActionProxy.
4. 4. ActionProxy reads the information of action and interceptor stack from configuration file using configuration manager (struts.xml) and invoke the ActionInvocation.
5. 5. ActionInvocation calls the all interceptors one by one and then invoke the action to generate the result.
6. 6. action is executed ActionInvocation again calls the all interceptors in reverse order.
7. 7. Control is returned to the FilterDispatcher.
8. 8. Result is sent to the client.

Note: Struts 2 uses the ActionContext to store all the data for a request processing. ActionContext work on the ThreadLocal concept i.e. unique values for every thread. That’s why it is thread safe and we don’t have to make our action thread safe explicitly.